As compared to acrylic pressure-sensitive adhesive compositions, silicone pressure-sensitive adhesive compositions are superior to the former in their electrical-insulation properties, resistance to heat, resistance to frost, and adhesion to various substrates. Therefore, the silicone pressure-sensitive adhesive compositions find application in the production of such goods as heat-resistant adhesive tapes, electrically insulating adhesive tapes, heat-seal tapes, masking tapes for metal plating, etc. In terms of mechanisms of curing, the silicone pressure-sensitive adhesive compositions can be divided into compositions curable by an addition reaction, condensation reaction, or a radical reaction with the use of organic peroxide, of which the silicone pressure-sensitive adhesive compositions curable by an addition reaction find more common application since they can be cured by merely retaining them at room temperature or by heating for acceleration of curing. Another advantage of these compositions is that they do not form by-products.
U.S. Pat. No. 5,190,827 discloses a silicone pressure-sensitive adhesive composition comprising: (A) a toluene soluble, resinous copolymer comprising R3SiO1/2 units and SiO4/2 units, wherein R is an alkyl group or alkenyl group, (B) an alkenyl-terminated diorganopolysiloxane, (C) a hydride-terminated organohydrogenpolysiloxane, (D) a hydrogen-containing diorganopolysiloxane, (E) a hydrosilylation catalyast, and (F) an organic solvent. And U.S. patent application Publication Ser. No. 2011/0097579 discloses a silicone pressure-sensitive adhesive composition comprising: (A) a branched organopolysiloxane having on average at least two alkenyl groups on molecular terminals, (B) an organopolysiloxane composed of R′R″2SiO1/2 units and SiO4/2 units, wherein R′ represents an alkyl group, alkenyl groups, aryl groups, or a hydroxyl group, and R″ represents an alkyl group, (C) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule, (D) a platinum-type catalyst, and (E) an organic solvent.
However, the silicone pressure-sensitive adhesive composition must be cured by heating at temperatures of at least 130° C. in order to convert them into the pressure-sensitive adhesive, wherein the residual solvent can be reduced. As a consequence, they cannot be used with poorly heat-tolerant substrates.